Workers' compensation benefits are not paid for any period that a worker is receiving vacation pay.
Whether you continue to accrue vacation time while out on workers' compensation is up to your employer. If there is a collective bargaining agreement in place, you will need to check with your union.
Generally, whatever vacation time you have when you get terminated, your employer should pay you for. However, questions about vacation pay owed to a terminated employee should be addressed to the Attorney General's Office of Fair Labor and Business Practices, 617-727-3465 because the issue does not fall under the jurisdiction of the Workers' Compensation Law or the Department of Industrial Accidents.